This program project will investigate the epidemiology of dementia in the urban community of North Manhattan, also known as Washington Heights-Inwood. This interdisciplinary investigation will focus on the epidemiology of the three common causes of dementia in the elderly: Alzheimer's disease, Stroke and Parkinson's disease. The study is centered in a heterogeneous community containing three major ethnic groups: Hispanic, Black and White. Columbia Presbyterian medical Center is the only hospital serving this community, where 35,043 people over the age of 60 live in an area of about 10 square miles. The current investigation consists of three projects: 1. The North Manhattan Aging Project, a cross-cultural method to develop a registry in order to examine the prevalence and incidence of dementia in the community; 2. The Incidence of Dementia with Stroke, a community-based, hospital investigation of the epidemiology of dementia following stroke; 3. The Epidemiology of Dementia in idiopathic Parkinson's Disease, a community-based investigation of the prevalence, incidence rate and risk factors for dementia in idiopathic Parkinson's disease. The these projects are supported by three cores: Administration (including data management and statistics); Clinical-Diagnostic (including genetics and epidemiology); and Neuropathology. This program projects is centered around a unique, culturally diverse community. We intend to investigate the cultural differences in the rates, types and causes of dementia, and, where possible, examine cultural differences in risk factors for dementia.